Virtual Environmental and Humanitarian Adviser Tool – (VEHA Tool) is a tool
to easily integrate environmental considerations in humanitarian response. Field Implementation guidances are useful for the design and execution of humanitarian activities in the field.

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VEHA - Field Implementation Guidance

Water supply, Sanitation and Hygiene Promotion (WASH)
Access to sanitation
Access to sanitation
Reuse of wastewater and sludge

Reuse of wastewater and sludge


Environmental factors causing/contributing to the needs and affecting the humanitarian activity

Water pollution can affect people’s health. Bacterial, viral and parasitic diseases such as typhoid, cholera, encephalitis, poliomyelitis, hepatitis, skin infection, and gastrointestinal diseases can spread through polluted water increasing the probabilities of overloading the capacity of excreta management systems due to diarrhoeal and vomiting cases. This impacts efficiency and capacity (that is increased amount of excreta generated due to health burdens).

In addition, close proximity of water tubewells and latrines together with soil porosity, ground water table, topography, drainage, and stability of slopes, may result in pollution of wells from surface water, sewage, solid waste leachates, chemical spills, etc and subsequent sickness or disease.

Gender, age, disability and HIV/AIDS implications

Soil and water pollution and eutrophication contaminants usually impact the poorest and most vulnerable members of society as they have less money and access to cleaner water.


Environmental impact categories

Soil pollution
Water pollution
Natural Resource depletion
Loss of biodiversity and ecosystems

Summary of Impacts
Summary of potential environmental impacts

Soil pollution and water pollution and eutrophication due to reuse of polluted water.

Impact detail
Detailed potential environmental impact information

Final treated effluent from wastewater treatment should be of sufficient quality that it can be released into watercourses or captured and transported for safe re-use, for example in small- or medium-scale agriculture, reducing demand for other water sources. On-site wastewater reuse can reduce water consumption as well as the amount of wastewater generated. This also reduces the risks of vector transmission through water stagnation. However, water must be tested to ensure it is safe to re-use or there is a risk of water pollution, soil pollution, water eutrophication, and even potential disease spread.

Because of the presence of organic, inorganic, and microbial pollutants in wastewater/septage, it is essential that it is treated before reuse for any purpose in order to avoid the pollution of soil, crops, and nearby water sources, and the likely spread of waterborne diseases or the degradation of soil.

Due to the variety of microorganisms in untreated wastewater, there is a high risk of disease outbreaks for farmers and consumers if wastewater/septage is not treated properly prior to final effluent capture and re-use.


Summary of environmental activities

Test and determine the most appropriate treatment processes for the wastewater or sludge. Test final treated effluent to ensure it is safe for reuse.

Detailed guidance for implementing suggested environmental activities

Test and determine the most appropriate treatment processes for the wastewater or sludge that is being received at wastewater treatment works.

Design wastewater treatment processes to effectively clean wastewater and sludge in compliance with national or international standards; provide regular on-site testing of final effluent and by-products and determine the most appropriate re-use or disposal in order to avoid harm to the environment. Environmental surveillance through regular testing should be conducted to ensure harmful microorganisms are not spread through wastewater reuse.

Design greywater diversion systems for handwashing facilities and showers to divert or capture and transport this water for use in toilets or agricultural activities. Ensure regular testing against national standards to avoid transferring biohazards to agricultural land. Systems can be designed to collect water from household or community/camp showers and basins and repurpose it. Open and stagnant water bodies should be avoided in the diversion and storage of greywater as these provide habitats for disease vectors to breed.

When proposing new treatments or uses for waste, ensure local authority consultation and approval. Look for opportunities to develop local government and community schemes to increase uptake of the solution after the emergency is over. This may result in improved excreta management in the community over the long term, reducing overall impacts on the environment.

Lessons Learnt
Lessons from past experiences

If cultivated in High Rate Algal Ponds (HRAPs), microalgae can both treat wastewater and be a source of biofuel. The algae grown in wastewater treatment processes can be extracted and used as feedstock for fuel through anaerobic respiration for biogas, lipids to biofuel, or carbohydrate fermentation to bioethanol. This option is attractive for its reuse of resources: HRAP systems which exclusively cultivate feedstock for biofuel are more costly and resource-intensive than land-based biofuel sources, however, if combined with wastewater treatment, nutrients and water that would otherwise be wasted can be put to use (Park et al. 2011).

Pittman et al. refer to a species of Chlorella grown in a municipal wastewater oxidation pond in India to demonstrate the effect that additional nutrient inputs have on biomass. Acting as a photoheterotroph, the algae produced biomass of 379 mg/L after 10 days, compared to 73.03 mg/L as a photoautotroph (Pittman et al. 2011). This suggests that in an HRAP system, algae could be a viable source of biomass production. Additionally, high CO2 content produces greater biomass.

If anaerobic digestion produces biogas on-site, the exhaust from that energy generation could be used as a CO2 input, making the system up to two times more productive with proper amounts of CO2 (Park et al. 2011). While a number of other factors contribute to algal biomass production including algal species, pH of the water, light saturation, lipid production, and nutrient availability, with proper design, experimentation, and implementation, these parameters can be addressed.

When cultivated in partnership with wastewater treatment, algae can be a feedstock source for biogas, simultaneously providing sustainable energy and reducing the effects of eutrophication. Though more research is needed to determine the practicality of joint wastewater-biogas projects, many high-rate algal ponds are currently used on a small scale for water treatment, particularly in small communities (Park et al. 2011). Potential lies within using the algae grown as a fuel source, which would reduce water and arable land used currently to grow soy and corn for bio-ethanol, and reduce the effects of eutrophication by consuming nitrogen and phosphorous before it reaches the ocean.

Activity Measurement
Environmental indicators/monitoring examples

Percentage of water that is recycled following safety and quality measures

Activity status
Main Focus
Focus of suggested activities

Mitigation of environmental damage

Resource implications (physical assets, time, effort)

Time and resources to test and treat wastewater or sludge prior to any re-used.

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